1. Topic
Electromagnets
Level
Key Stage 3 (or any course for students aged 11-16)
Outcomes
To know that when current flows through a wire a magnetic field is produced. The size of this magnetic field can be increased by using an iron core, adding more turns to the wire and increasing the current flowing through the wire.
Information for teachers
This activity has been designed to motivate students to investigate electromagnetism. After a demonstration introducing students to electromagnets, students compete to build an electromagnet that can transport exactly 5 paper clips a distance of 1 m. By doing this they will explore the relationships between current, coils and magnetic field strength. You may want to test out the method first to make sure that 5 paper clips is an appropriate number to use.
Working in groups of 2 students have 15 minutes to build their electromagnets before they are tested at the front of the class. Using the table on slide 5 you can then find the winner. Share this information before students begin the challenge.
Please risk assess this practical before carrying it out.
| resources for science teachers who like to think

2. Demonstrate how to make an electromagnet
Key points:
when current flows through a wire it creates a magnetic field around the wire
the strength of the magnetic field can be increased by adding an iron core and increasing the number of coils
we can reverse the magnetic field by changing the direction of the current
the magnetic field can be turned on and off.

3. Electromagnets
Bar magnets

4. You have the following items.
Your challenge: create an electromagnet that will pick up, transport and release exactly 5 paper clips over a distance of 1 metre.
A power pack
A push button switch
An iron nail
A length of insulated wire
Crocodile clips
20 paper clips
Circuit wires
Drop only 5 paper clips into the cup!
Pick up only 5 paper clips from this pile of 20
Transport the paper clips over a distance of 1m.
You cannot touch the paper clips.
1 m

5. Distance travelled before the first paper clip drops (cm)
Group name
Distance travelled before the first paper clip drops (cm)
Paper clips in the cup
Deduct one mark for every paper clip over or under 5 (max 5 points)
Total Score:
Distance x Paper clips in the cup
(max. 500)